The Coast Guard is warning any boaties out on the water to move into deeper water, with a tsunami warning in place for much of the North Island on Friday.
The warnings come after three earthquakes this morning. The first one measured magnitude 7.3 and was located 105km off the coast of New Zealand's North Island. That was followed by two in the Kermadec Islands, measuring magnitude 7.4 and 8.1.
Kiwis on land have been urged to head to higher ground, while those at sea are being advised to ride out any tsunami in deeper water.
"Our messaging to boaties at the moment is if you're out there already then get to deep water and ride this thing out and wait for the all-clear," Coast Guard operations manager Rob McCaw told Newshub on Friday.
"If you're thinking about going out then just don't, and if you're somewhere near shore then push further out to sea - don't risk trying to recover right now."
McCaw said the Coast Guard had received a number of reports of boats out on the water, with many who had loved ones out at sea also getting in touch.
"Our main operations centre in Auckland has been inundated with calls from parents, wives, boyfriends, etc of people who are currently out fishing or on boats, and wanting to know that they're ok."
So far there have been no distress calls relating to the threat of a tsunami, he said.
For those out at sea, McCaw said they should ideally be at least 50 metres from the shore, "but the deeper the better".
"[That] will get you into a body of water, that depth of water, to just absorb most of that pressure from the tsunami which means you're going to ride it out a lot easier," he said.
Any boats located near an entrance to a harbour, near a river bar or an estuary were in particular danger, he said.
McCaw also had a warning for people thinking of going to rescue their moored vessel: "Don't.
"It's genuinely as simple as that. We've seen the stream of footage of people leaving their homes with their family and loved ones and getting to higher ground. If people are willing to leave their homes then leave your boat behind too - it's not worth it. Focus on your own wellbeing and that of your whanau; things can be replaced, family can't."
Footage circulating on social media appears to show strong ocean surges in places like Tutukaka and Tokomaru Bay.
McCaw said boaties could expect to see difficult ocean conditions for a while yet, even after the initial risk of tsunami disappears.
"There will be a continued threat of tidal surges, dangerous currents and that kind of thing, and that will hang around for a long time."